IBM Launches one puzzle every month in its "Ponder This" section. I just came to know about it day before yesterday and sent my solution for the active challenge.
Check my name at http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/challenges/October2009.html
The Puzzle is not mathematical though :P
Complete the following sequence:
1, 13, 2, 1, 5, 3, 2, 1, 4, 4, 7, 3, 1, 5, 3, 5, ?, ?
Hint: The solution is related to a quote about mathematicians.
You can do it only if you know it. Thinking does not really help!! :)
PandeyJi (Nikhil Pandey) said that he was able to solve it. :)
Solution: IBM guys will post it on their link in 2 days anyways! :)